External Impingement
Clinical Presentation
Clinical Features:
- Patients present with painful arc
- Pain at night
- Pain over deltoid
- Due to loss of space under 'coracoacromial arch'
Clinical tests are not always clear cut - see Jobe test video. Imaging goal is to differentiate patients with bursitis/tendinopathy from tears. Clinical examination is not always accurate despite the numerous clinical tests that are available. Not all cuff tears are painful and not all require surgery.
SASD Bursa:
The SASD bursa is a large bursa that separates deltoid from the rotator cuff tendons. Impingement symptoms occur when there is inflammation of the bursa usually due to loss of subacromial space.
The SASD bursa is a large bursa that separates deltoid from the rotator cuff tendons. Impingement symptoms occur when there is inflammation of the bursa usually due to loss of subacromial space.
This can occur for complex reasons including:
- Genetic predisposition
- Scapular re-orientation due to muscle imbalance (Sick Scapula)
- Bony impingement related to AC shape and osteophytes
- Enlarged tendon due to tendinopathy
Imaging Considerations:
- Clinical relevance of different acromial shapes in some doubt
- Hooked acromion probably not a relevant finding
- Acromial slope more important, especially if less than 70 degrees
- Report Os acromiale if present
- Look for tendon calcification